Carburizing process



N. E. PHILLIPS CARBURI ZING PROCESS Nov. 1 7 1925- Filed Aug. 27, 1923SNN l. 411/... flu K: u

7 to remove the scale.

lPatented Nov. 17, 1925.,

N ORA E. PHILLIPS, 0F CHICAGO, ILLINOIS.

GARBURIZING rRocEss.

Application led August 27, 1923. Serial No. 659,501.

To all whom t may concern.'

Be it known that I, NORA E. PHILLIPS, a citizen of the United States,having residence at Chicago, in the county of Cook and the State ofIllinois, have invented certain new and useful Improvements inGarburizing Processes, of which the following is a specificationreference being had to the accompanying drawings, forming a partthereof.

The rpurpose of this inventin is to provide an improved method andprocess of carburizing ferriferous metal, as cast iron, malleable orwrought iron. It consists in the employment of the materials indicatedand the steps of the operation as hereinafter fully described, all asindicated in the claims.

The drawing shows an apparatus suitable for carburizing in accordancewith the invention, Figure l being a vertical longitudinal section, andFigure 2 a vertical transverse section of a muiile furnace charged witha body of iron to be carburized and with the carburizing materialdisposed in relation thereto for effecting the carburizing according tothe process of the invention.

In the practice of the invention consisting of this process, dioated atA in the drawings, is packed in charred leather, indicated at B, thispacking having a thickness of from two to three incheson lall sides andbeing surrounded with an outer layerr of bone-meal or other pulverulentcalcium bearing substance indicated at C, the entire package beingencased in a metal box or mufiie, D, which is ex-v posed to heat in asuitable furnace or jacket, as indicated at E, and maintained at whiteheat of the metal, A, for a period of time which may vary from four toten hours according to the thickness of the metal or depth ofpenetration for carburiz'ing whichv y is desired. For completelycarburizing pre-y paratory to hardening a cast ironbar one lnch inthickness, the above mentioned temerature conditions should bemaintained R or approximately six hours.

The metal is then ing and as quickly as possible is immersed in asaturated solution of salt water for about 15 minutes,

bath and immersed in Gray cast iron, treated bythe above proc ,from twoto three inches deep,

the metalto be treated, in-V removed from the pack` causing theformation of a loose scale; it is then removed from the salt water asulphuric acid bath ,b

ess, is thereby rendered suitable to carburization, hardness, andcapacity for tempering, for ordinary tool purposes; and the texture isrendered such that a milling cut presents the appearancefof a milledsurface of a good quality of tool steel.

Malleable iron castings and wrought iron, treated by this processbecome, for all purposes requiring hardness, toughness, andsusceptibility to tempering, equal to the best grades of carbon steel. Q

In detail, the process is performed as follows: In the metal box ormuliie, D, which should be from three to five inches larger in eachdimension than the piece or group of pieces of-metal to be treated,there is first deposited and tamped in fairly hard, a layer ofbone-meal, one. inch deep." Upon this bed of bone-meal, there is set atemporary retainer, F, which comprises merely encompassing walls withouttop or bottom, dimensioned both horizontally and vertically from four tosix inches larger than the piece of metal or group of metal pieces to betreated. In this retainer 'there is deposited and tamped down, a layerof charred leather and upon this bed of charred leather, the metal to betreated is laid and covered with and enclosed in charred leather, tampeddown fairly hard. Thespace around the retainer is then filled withbone-meal to the level of the top of the charred leather within theretainer, the bonemeal being tamped down firmly. The retainer is nou7withdrawn and the muliie box is filled to the top with: bone-meal, theremaining space for the same being substantially the same as to depth ofthe bottom layer of bone-meal. YA tight cover, D1, is then applied tothe muflie box, and it is placed in the furnace or other means ofapplying heat. For this purpose I have usually provided a brickstructure such as shown at E in the drawings, forming a chamber severalinches 'larger in every dimension than the muiie box, mounted in anyconvenient chamber and the space around same bein filled with charcoalor coke or other suitab e fuel, which, being ignitedv and maintained inburning condition` by suitable draft, heats the box and contentstoxthetemperature ineing treated. I

It is to be understood' that the partlcular in respect the latter beingy manner 1n this dicated, viz, whitevheatfoffthe nieta1, A, n

mechanical ineens pf the nature of a ful l0 1y consoiioieted pecking; ofpu nace for heating the muie box and contents, is :i metter ofconvenience, the picoeess irequiring simply that the package hemeinteiiied et White heat of the metai treated for 5 the 'necessary timeto cause the desiie depth of tempel "cure of the caihiuiziig element.

1. rhe pi'ocess of caibuiizing ii'oii, which consists iii inciosiiig theii'on Within a dose* iveiuient car bonieious substance of substantielthickness enclosed in e similarly consolidatedstance, and subjecting thepackage to a teinperetuie for heating the enclosed package andmaintaining the same at White heet of the eiiciosed ii'on for from ourto ten hours according to the depth of carburization desired.

2, iin the process 'set forth in claim i foregoing, the employment voit'cham-ed leather as the ceibuiizing materiel.

ihn testimony whereof, have hereunto eet my hand et Chicago, illinois,this 17th day of August, 1923.

\ NRA E. PHLLPS.

